A hybrid vehicle is known that includes an engine, an electric motor, a clutch disposed in a power transmission path between the engine and the electric motor, and a hydraulic power transmission device with a lockup clutch disposed between the electric motor and drive wheels. For example, a parallel hybrid power train 1 (power transmission device) of Patent Document 1 is an example thereof.
Patent Document 1 describes that when the engine is started from motor running using the electric motor, a shock due to torque variation generated at the time of engine start is suppressed by slip operation of the lockup clutch.